Prime Minister David Cameron will today weds pledge that a Conservative Government would hold an in-out EU referendum in the first half of the next parliament.

Prime Minister David Cameron will today pledge that a Conservative Government would hold an in-out EU referendum in the first half of the next parliament.

In a landmark speech on the future of the UK’s relationship with Europe he will warn that “democratic consent for the EU in Britain is now wafer thin.”

But he will unequivocally state that “Britain’s national interest is best served in a flexible, adaptable and open European Union.”

He will say: “The next Conservative manifesto in 2015 will ask for a mandate from the British people for a Conservative Government to negotiate a new settlement with our European partners in the next parliament. And when we have negotiated that new settlement, we will give the British people a referendum with a very simple in or out choice to stay in the EU on these new terms; or come out altogether.

“It will be an in-out referendum. Legislation will be drafted before the next election.

“And if a Conservative Government is elected we will introduce the enabling legislation immediately and pass it by the end of that year. And we will complete this negotiation and hold this referendum within the first half of the next parliament.

“It is time for the British people to have their say. It is time to settle this European question in British politics.”

He will add: “I believe something very deeply. That Britain’s national interest is best served in a flexible, adaptable and open European Union. And that such a European Union is best with Britain in it.

“Over the coming weeks, months and years, I will not rest until this debate is won; for the future of my country; for the success of the European Union; and for the prosperity of our peoples for generations to come.”

UK Labour leader Ed Miliband yesterday said the speech would “define him as a weak prime minister, being driven by his party, not by the national economic interest”.

He said: “In October 2011, he opposed committing to an in-out referendum because of the uncertainty it would create for the country. The only thing that has changed since then is he has lost control of his party and is too weak to do what is right for the country.”

He added: “This speech will do nothing for a young person looking for work, for a small business worried about a loan, for the family whose living standards are squeezed.”

However, Mr Cameron will argue that “public disillusionment with the EU is at an all time high.”

Rejecting charges that saying this “creates uncertainty for business and puts a question mark over Britain’s place in the European Union,” he will argue: “[The] the question mark is already there and ignoring it won’t make it go away. In fact, quite the reverse.

“Those who refuse to contemplate consulting the British people, would in my view make more likely our eventual exit. Simply asking the British people to carry on accepting a European settlement over which they have had little choice is a path to ensuring that when the question is finally put – and at some stage it will have to be – it is much more likely that the British people will reject the EU.

“That is why I am in favour of a referendum. I believe in confronting this issue – shaping it, leading the debate not simply hoping a difficult situation will go away.”

Welsh Ukip MEP John Bufton the EU had “no appetite” for renegotiation.

He said: “The only viable option is an in-out plebiscite and that is one that I and my party fully support”.

Plaid Cymru MEP Jill Evans said: “We demand a clear commitment from the UK government that in the event of a referendum, the Welsh result will be declared separately. Plaid Cymru secured such a commitment when a referendum was proposed on the EU Constitution in 2005.

“In the event of Wales voting Yes and England voting No, negotiations would have to take place on the way forward. The constitution of the UK is changing and the role of Wales within it is changing too.”

Carmarthen West and South Pembrokeshire Conservative MP Simon Hart was confident the UK’s relationship with the EU would change.

He said: “It ain’t going to be like it is as it is now... The one thing that unites everybody is the current arrangements are by and large pretty unsatisfactory.”

Acknowledging the likelihood of opposition among EU members, he said: “If that makes the Europeans squeal a bit, so be it.”

But Labour peer and former Welsh MEP Eluned Morgan said: “It’s not just one member state you have to convince; you have to convince every single one.”

She warned: “I think they are losing patience with Britain.”

Arguing that important social and environmental legislation had its origins in the EU, she warned that leaving would damage the UK’s “special relationship” with the US and weaken Britain’s position on the world stage.